English (pdf)
Article in xml format
Article references
Automatic translation
Send this article by e-mail
Cited by SciELO 
Cited by Google 
Similars in
SciELO 
Similars in Google 
Permalink
1. Introducción
Hunger and poverty are problems faced by the rural sector today. It has been estimated that almost half of the rural population is poor and a third live in extreme poverty; most of the farmers work in small-scale agriculture as their main means of subsistence, based on family labor (FAO, Regional Office for Latin America and the Caribbean, 2017), and are classified as "agricultural producers, livestock farmers, foresters, small scale fishermen and resource-limited fish farmers".
In Colombia, one of the livestock activities developed within family agriculture is rabbit breeding, defined as"reproduction process in an economic way, aimed at obtaining maximum profit from the sale of products and by-products of rabbit breeding and fattening" (Never, 2018), as quoted by Vargas and Castilla (2011). It has been a promising activity for the generation of animal protein of excellent quality in developing countries where most of the food production is generated by farmer families with 79% participation in food generation for household consumption, contributing to the country's food self-sufficiency (Comité Nacional de Impulso Colombia, 2014). Rabbit breeding as well as other livestock production has been affected by the continuous increases in cost of conventional raw materials such as grains and cereals, about which Silva et al, 2000; Retore et al, 2008 (as quoted Al-Dobaid, 2010), state that diets based on corn flour and soybean increase meat production costs (Bonilla, Delgado y Mora, 2016), generating in turn, a rise in human food prices since much of the grains are the main components of industrial foods.
In recent years, new nonconventional forage alternatives for animal feed that do not compete with human feeding and are readily available in the environment have been sought (Calvache, 2005; Palma and Hurtado, 2009), such as giant taro (Alocasia macrorrhiza) and balu (Erythrina edulis), forage plants with multiple benefits. Commercial rabbit production has been adversely affected by the high cost of feeding and use of traditional feed stuff (grain and soya bean) that have direct competition with humans for food. There has been an unbearable continued increase in the cost of traditional feed resources (soya been, maize, millet, groundnut, fish meal etc.). Diverse plant materials and industrial byproducts in different agro ecological regions of the world have been assessed for their nutritive potentiality as alternative feedstuff ingredients, these include: water spinach (Hongthong, Siton, Chhay y Preston, 2004), wheat bran (Falcao-e-Cunha, Peres, Joao y Castro-Solia, 2004), rape seed (Gasim-Boubaker et al., 2007), gliricidial leaf meal (Amata and Bratte, 2008), groundnut haulms and cowpea shells (Bawa et al.. 2008), paper mulberry (Inthapanya and Preston, 2009), olive pulp (Mehrez and Mousa, 2011), sweet potato fodder (Elamin et al.. 2012), white lupin grain (Zwolinski et al., 2017) etc. the list is inexhaustible because the nature of local feedstuff depends on geographical ecological regions and plants resources.
The objective of this research was to evaluate the effect of diets with nonconventional forage resources, balu (Erythrina edulis) and giant taro (Alocasia macrorrhiza), on productive parameters of New Zealand white rabbits (Oryctolagus cuniculuss under family farming production in Silvania (Cundinamarca).
2. Materials y methods
Location and description of the area
This research was conducted on Lusitania farm, Santa Rita village, municipality of Silvania, Cundinamarca, in the Sumapaz region, 49 km from the city of Bogota, 1,850 m.a.s.l, average temperature between 17 ° and 20 ° C, 85% annual relative humidity, 1,653 mm/year rainfall. The municipality has a total area of 163 km2 of which 7.48 km2 are urban areas and 155.44 km2 are rural (Castellon, 2014).
Animals and Equipment
36 white New Zealand rabbits of 35 days old were used; they were housed in 8 galvanized cages with 0.5 x 0.5 x 0.4 m dimensions, metal troughs and automatic drinking troughs (Henao, Gutierrez and Oviedo, 2012; Bonilla, Delgado and Mora, 2016).
Diet elaboration
Diets based on balu (Erythrina eduliss and giant taro (Alocasia macrorrhiza) leaves flour, were carried out as reported by Gutierrez, Henao and Oviedo (2014).
Cutting
A 4 year-old giant taro culture and a 6 year-old balu culture were used. Regarding giant taro, 45 to 50 day-old bud leaves were cut, that is to say, those with a green brilliant color; leaves with brown or yellow spots were not used, and care was taken when cutting the leafstalk, with a cut in diagonal near the stem or corm. Regarding balu, young leaves of all the tree stratum were cut. Besides, a straw chopper was used to reduce the particles size, which allowed better drying of the material. Next, drying was done on a forced air circulation stove for 48 hours, at 65°C to ensure lower humidity without altering the compositional quality of the plant material.
Pellet Processing
Using giant taro (Alocasia macrorrhiza), balu (Erythrina eduliss flour and commercial pet food, pellets were made for each diet:
Mix of raw materials to obtain homogenization and according to the proportions regarding the diet set.
Homogenization: according to the methodology used by Gutierrez, Henao and Oviedo (2014), raw material was mixed and then moistened with a water solution and molasses at 50 °Bx, until a homogeneous structure was obtained
Artisanal pelletizing in an industrial pelletizer of the nutrition laboratory of the University of Tolima.
Pellet drying at room temperature.
Diets implementation and their corresponding treatment
Diets corresponding to the different treatments are described below:
Chemical analysis of flour
500 g flour were obtained at random for each raw material and diet. The flour was packed in hermetic bags with their corresponding identification; then the samples were sent to Laserex laboratory of the University of Tolima, to determine by means of a bromatological analysis, the percentages of nutrients contributing: dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), ethereal extract (EE) and ashes (AS), according to the methodology described by AOAC (1995), (Acosta et al. (2016).
Feed frequency
The rabbits were fed according to the diet established for each treatment. The food required was provided in two daily rations, according to their age: at 7:30 am in the morning, and at 4:30 pm in the afternoon because according to Read et al. (2016), although rabbits have a limited feeding behavior, they can consume pelleted food quickly, which generates a hunger state during part of the day, creating stereotypical behavior to famine and the frustration for not consuming forage.
Productive Parameters
Production parameters evaluated during the experimental period:
Initial live weight (ILW): which was measured on day 35, when rabbits were weaned. Each one was weighed and the initial average weight of each treatment was determined.
Final live weight (FLW): it was determined at week 8 post-weaning, when the experimental period ended; each rabbit was weighed on a digital scale to determine the final average weight of each treatment.
Average Daily Weight Gain (ADWG): According to Palma and Hurtado (2010), it was determined, based on the weekly weight gain divided into the 7 days of the week, which resulted in the weight gain in grams gained by a rabbit in 24 hours.
Feed consumption: it was determined by weighing the food supplied daily minus the food not consumed (rejected) for each treatment.
Feed conversion: According to (Cano and Dohigo, 2012) it is a practical measure to calculate the efficiency with which animals use the food ingested for their growth, which is calculated through De Blas 1989's formula, quoted by Palma et al, 2010. Feed consumption divided by final weight, minus initial weight, and it is expressed in kg of food consumed per kg live weight (LW).
All the parameters listed above were taken every week on a specific day, with the time settled during the whole experimental period.
Animal slaughter
The rabbits were slaughtered to determine the parameters of productive quality. Slaughter was carried out by the numbing method described by Rodriguez (2002); the rabbits were gutted and quartered immediately after slaughter, a process in which the head, hands, legs, skin and viscera were removed.
Statistic Analysis
Productive parameters were initially analyzed by means of variance analysis (ANOVA) at a 95% accuracy level, a Tukey multiple comparison test at 5% significance level, and an orthogonal contrast between the control treatment (Tl) and the other treatments. A multivariate analysis of variance (MANOVA) was carried out to evaluate whether there was any treatment showing a better behavior, regarding the productive parameters as a whole. And Hotelling comparison test was carried out at a significance level of 5%. The previous tests being accepted only if they fulfilled the assumptions of normality, variance homogeneity and error independence verified by means of Shapiro-Wilks, Levene and Durbin-Watson tests, respectively.
3. Results and Discussion
Flour nutritional contribution
Table 1 shows the nutritional composition of balu leaf flour (Erythrina eduliss y and giant taro leaves flour (Alocasia macroorrhiza)
Table 1 Nutritional composition of balu leaves flour (Erythrina eduliss and giant taro leaves flour (Alocasia macroorrhiza).
Source: The authors
Additionally, this tables shows the nutritional composition of the raw materials used in the experiment, which were determined by bromatological analysis according to the methodology described by the AOAC (1995).
As for the nutritional contribution of the flours of the legumes used, it can be stated that balu is a tree legume native of the Andean region and used by the ancestors in human and animal feeding, due to the high contents of nutrients present in the fruits and leaves. Inciarte et al (2015), reported an update of the nutritional content of I balu or chachafruto leaves in Merida, Venezuela, finding 24% protein contribution, 29% fiber, 3% ethereal extract and 9% ash, similar results to those found by Delgado and Albarracin (2012) which evaluated the compositional contribution of balu flour, obtaining 22.8% proteins and 0.70% fat percentage as possible extenders for meat products.
Furthermore, the nutritional composition of giant taro (Alocasia Macroorrniza), although a little lower compared to balu, also showed high content of proteins and essential amino acids. This fabaceous species has been used in the feeding of pigs, birds and fish. Mora - Valverde (2015) reported a protein and fiber content was 22.4% and 15.4% respectively. Similar result to that reported by Basto Gomez (1995) where the percentage of protein is 21.0 - 22.0%, higher than that found by Moreno (2002) with protein levels between 13.6% and 15.4%, which are lower than those reported in this research. As for ethereal extract, Muñoz Valderrama (2011) showed levels of 3.1% in whole giant taro leaves, a lower value than the one found in this study, while fiber found in giant taro leaves represents 15.4%.
The productivity of the different animal species depends to a great extent on the nutrients provided by the supplied diet, in the case of this research it can be mentioned that the percentage of protein provided by the Giant taro and Balu, it is significant since comparing it with another type of food used in rabbit production, is above the reported values (Aguda and Omage, 2014), indicating that they are a promising alternative for animal feeding; Likewise, the importance of the nutritional quality of the different vegetable raw materials can be shown, since the content of fiber, lignin, minerals and proteins are keys to success in weight gains, growth rates behavior and reproductive performance, among others (Lee, 2018).Table 2 shows the bromatological composition of the diets provided in each treatment.
Table 2 Bromatological composition of the diets provided in each treatment. DIETS
| PARÁMETERS | GIANT TARO | BALU | GB | CONTROL |
|---|---|---|---|---|
| Dry matter % | 94 | 95 | 81.3 | 86.2 |
| Protein % | 16.4 | 17.4 | 19.1 | 17.3 |
| Fiber% | 14.3 | 16.6 | 18 | 11 |
| Ethereal extract% | 10.3 | 9.3 | 0.8 | 4.3 |
| Ash % | 10 | 8.2 | 9.9 | 10.7 |
Source: The authors
An increase in the percentage of dry matter and the ether extract is observed in comparison to Table 1, for the values of fiber and protein, a decrease in the percentage of these components was observed in the different diets.
In the case of the dry matter (DM) content (%) of rations from different trataments ranged from 94 to 86.2 para and showed no difference among the treatments.
According to the study, the percentage of protein for the Giant Taro + Balu (GB) treatment is the highest with respect to the other treatments, however there was no significant difference, therefore, to consider the GB diet as a good source of protein, the inclusion level must be considered, since as the amount of raw material increased, the protein also increased.
The protein percentage of the Giant Taro, was lower than reported by Girata, Lozano, Tarazona, Aguilar and San Miguel (2013) who found protein contents of up to 25% in the Giant Taro leaves and also reported 10% fat content and high concentrations of A, C vitamins and minerals, are results close to those reported in this research that indicate that the Giant taro is a plant that has special characteristics to be used in feeding birds and other livestock productions.
Production parameters
Post-slaughter Parameters
At the end of the experimental period at 90 days old, the rabbits showed a final weight or a live weight at slaughter higher than 2 kg (Table 3), an internationally established value for marketing rabbits in fattening (Ortiz, Motta, Anchieta, Moraes y Lezcano, 2013).
Table 3 Productive behavior of rabbits fed with diets containing 25% giant taro and blu leaves and their mixture.
Source: The authors
Values with different letters within the same row indicate statistically significant differences (p<0.05),
Table 4 shows the variables related to the characteristics of the carcass of rabbits fed with diets containing 25% giant taro leaf flour, balu and their mixture. As for carcass yield variable (CY), no significant differences were observed in the giant taro treatment, relative to control treatment. However, significant differences were observed (p<0.05) for giant taro and control treatments, regarding balu and GB. Also, the carcass length showed difference (p<0.05).
Table 4 Characteristics of the carcass of rabbits fed with diets containing 25% giant taro and balu leaf flour and their mixture.
Source: The authors
Values with different letters within the same row indicate statistically significant differences (p<0.05)
Final weight (FW), feed consumption and feed conversion (FC), did not show significant differences (p<0.05) between treatments; however, differences (p<0.05) for weight variable at weeks 5 and 6 in giant taro treatment (1771.85±88.21 AB) were found; and control (1933.06±88.20 B), giant taro (1935.05±91.26 AB); control (2144.42±91.26 B) respectively. Daily weight gain showed significant differences (p<0.05) in week 5 for giant taro (33.56±2.82 AB), control (.37±2.82 B). Direct relationship with the rabbits productive behavior was revealed by data on the bromatological composition of the diets provided in each treatment. It was observed that the growth of rabbits distributed in the different treatments could be affected by the crude fiber content of these diets, and (Quintero, García and Peláez, 2007), state that the amount of fiber recommended is 10 to 15% for growth and normal intestinal functioning; therefore, diets with higher fiber values increase when passing through the intestine, reducing nutrients digestibility and absorption, affecting feed conversion and daily weight gain up to 30% to 50% (Trocino et al., 2013). However, Gidenne et al (2017) state that diets with more than 25% fiber in acid detergent (FDA) reduce food consumption, preventing the supply of digestible energy needs for an optimal growth rate. In contrast, when fiber is reduced by less than 18%, rabbits can develop digestive pathologies; mucoid enteritis and coccidiosis.
Victoria et al. (2007) evaluated golden button flour ( Tithonia diversifolia) in three inclusiom levels of 15%, 30% and 40%, in diets for rabbits in growth stage, which presented a 14.3% crude fiber and 16% crude protein composition, finding significant differences (p<0.05) between treatments for the variable weight gain with 19.1 g/day and a 4.6 feed conversion, similar to that reported by Yasmania and Dihigo, (2012), who determined the productive behavior of rabbits fed with a 20% inclusion of dolicho and mucuna flour did not find significant differences between treatments. Feed conversions 4.56 are greater than those reported in this study.
On the other hand, 21.25 g/ rabbit/day daily weight gain in these experiments is similar to those obtained with the inclusion of flour from fruits and breadfruit leaves (Artocarpus altilis) in the fattening of 19 g/day white New Zealand rabbits (Leyva, Valdivie and Ortiz, 2012), being lower than those determined in this experiment. According to Lukefahr and Cheeke (quoted by Pronaf, 2012), daily weight gains obtained are adequate because rabbits bred in temperate regions have daily gains in the range of 30 to 40 g/day, while those bred in warm temperatures vary from 10 to 20g.
Protein percentage in diets is adequate for the requirements of rabbits in growth stage because levels above 18% do not present additional benefits; on the contrary, the incidence of enterotoxemias occurring when 20% is exceeded increases. It has also been suggested that high levels of this nutrient increase this metabolic problem and favors the proliferation of Clostridium spp. and E. coli (Mora-Valverde, 2010).
The nutritional content of different diets directly influences different parameters; carcass yield (CY) is an indicator that allows determining the productivity of an individual within a production. According to Leyva, Valdivie and Ortiz (2012) rabbits slaughtered at a young age present a reduction in carcass yield because this indicator tends to increase with age as muscle tissue has greater development; however, fat content is higher than that in young animals carcasses. Calvache (2005) evaluated rabbit feeding with mulberry supplied adlibitum, presenting 46.6%average carcass yields, similar to those reported by Leyva, Valdivie and Ortiz, (2012), who included fattening fruit flour and bread tree leaves in the rabbit serving size, finding 49.29% CY at 90 days old. Likewise, Lara, Itza, Sanginés y Magaña (2012), fattened rabbits with mulberry or tulip flour included in multinutritional blocks, obtaining 50% CY.
The Spanish rabbit breeding organisation (ASESCU) points that rabbits fed with commercial pellets reach carcass yield ranging between 50 to 65%, based on the animals' age (Galeano, 2017). However, rabbits fed with nonconventional raw material obtain a CY between 46% to 50% approximately, similar to that reported in this study. Variation in carcass yield can be influenced by the specimens age and the dietary nutrients availability. Molina et al. (2017) estimated the characteristics of the carcass in rabbits fed with Amaranthus Dubius, finding average value of 28.41% for loin yield and 39.28% for haunch. Also, Adeyemo, Taiwo and Adeyemi (2014), obtained 28.8% haunch yields in rabbits fed with forages. This value is lower than the one reported in this study.
On the other hand, morphometric measures are used to evaluate breed yields, predict live weight gain and they are also a productive yield indicator, Chineke (quoted by Galeano, 2017).
4. Conclusions
Rabbits fed with giant taro diet presented greater development and growth than those fed with balu; also, significant differences (p<0.05) for the weight variable in week 5 and 6 were observed. From here, it can be concluded that giant taro can be used as unconventional raw material in food manufactoring for rabbits in growth until week 6.
Giant taro is a non-conventional raw material that generates more gain in diets for rabbit feeding with 25% substitution of the commercial pellet. Besides, this diet did not present significant differences in productive variables regarding the treatment control (commercial pellet), being an alternative for the elaboration of rabbit feed with native raw material available in the region, which do not compete with human food and will promote sustainable agricultural production.
There are many unconventional fruits and foods available in the tropic land and they represent valuable sources of nutrients; thus, Giant taro and Balu appear as outstanding protein sources. However, the interest in a fruit or a non-conventional food for animal feed, will depend on its availability, flavor, acceptance by the species and the quantity to offer to cover its requirements; in this investigation the results showed that diets with nonconventional forage resources (balu and giant taro) are a viable alternative for animal feeding, due to their high nutritional content and as a by-product of commercial interest for rural families in areas of the middle Colombian tropic.
